A left-handed batsman, Bhanuka Rajapaksa made his first-class debut in 2011, after showing his caliber at the Under-19 level. The Colombo-born cricketer made waves during the U19 team's tour of Australia in 2009, where he finished as the tournament's leading run-scorer, which included a 111-ball 154 in a one-day game.
Rajapaksa was later chosen as a specialist batsman for the 2010 ICC U19 World Cup held in New Zealand, and had a sensational outing. He did not fail to live up to his reputation and emerged as his team's highest run-getter at the end of the competition, scoring 253 runs. In 2012, he represented Uva Next in the inaugural Sri Lanka Premier League and helped them clinch the title. He was also named in the Champions League T20 squad later that year.